Since the creation of Medicaid in 1965, poor single adults have never been eligible based upon income alone. Many states — including Maryland — ran fully state-funded programs providing equivalent benefits for this population, but these were almost all scaled back or eliminated in the lean budgetary years of the early 1990s.

As a result, many vulnerable people were ineligible for insurance for decades, no matter their level of poverty. Without access to care, they tended to get poorer, sicker and costlier to treat by larger health care system.

It may surprise many to learn that nationally and locally, only a small minority of folks experiencing homelessness — generally only families and those that can prove a disability — currently are eligible for Medicaid.

That will change on Jan. 1, when the large majority will be eligible for coverage in states that have embraced the opportunity to expand benefits to all adults with incomes up to 138 percent of federal poverty line — about half the country.

Maryland has taken strong steps to make the most of this reform for vulnerable people. Increased access to primary and preventive care, along with coverage for specialty care and hospitalization, will provide individuals and communities important resources to prevent and end homelessness.

To be sure, we have much work ahead of us to create the kind of cost-effective system that brings everyone in and leaves nobody out. But extending comprehensive insurance to most extremely low-income people through Medicaid expansion is an excellent place to start.